The present invention relates to a substrate processing apparatus, for example, for performing coating processing of a resist solution, developing processing, and the like for a substrate such as a semiconductor wafer, a glass substrate for a liquid crystal display, or the like.
In photolithography in a semiconductor device fabricating process, a resist is applied to the front face of a semiconductor wafer (hereinafter referred to as a wafer), the applied resist is subjected to exposure processing in accordance with a predetermined pattern and then developing processing, whereby the predetermined pattern of resist film is formed. Such a series of processing is performed by a system in which an aligner is connected to a coating and developing apparatus.
FIG. 12 is a plan view showing a conventional example of such an apparatus, and a cassette C housing 25 substrates, for example, semiconductor wafers is carried into a cassette stage 1 in a cassette station A1. On this occasion, the cassette C housing, for example, 25 wafers W is carried into the cassette stage 1 by an automatic transfer robot, and a transfer path 10 for the automatic transfer robot is formed along the cassette stage 1 outside and near the cassette station A1.
A processing station A2 is connected to the cassette station A1, and an aligner A4 is connected to the processing station A2 with an interface station A3 between them. The processing station A2 includes, for example, two coating units 11 each for coating the wafer W with a resist solution and, for example, two developing units each for developing the exposed wafer W, and these units are arranged with two tiers each with two units perpendicularly to the direction of arrangement of the cassettes C placed in the cassette station A1 (In this example, the developing units are arranged at the lower tier).
This station A2 also includes, for example, three shelf units 12, 13, and 14, in which the wafers W are mounted at multiple tiers, and respective shelves of these units 12, 13, and 14 are structured as heating sections, cooling sections, delivery sections for the wafer W, and the like. The wafer W is transferred between the coating units 11, the developing units, and the shelf units 12, 13, and 14 by a wafer transfer means 15.
In such a system, the wafer W in the cassette C on the cassette stage 1 is taken out by a delivery arm 16, sent to the coating unit 11 via the delivery section of the shelf unit 12, and coated with the resist there. The wafer W is then transferred through the wafer transfer means 15, the delivery section of the shelf unit 13, the interface station A3, and the aligner A4 so as to be exposed to light. The exposed wafer W is transferred to the processing station A2 by the reverse route, and after being developed in the developing unit which is not illustrated but provided at the bottom of the coating unit 11, the wafer W is transferred through the wafer transfer means 15, the delivery section of the shelf unit 12, and the cassette C. Incidentally, the numeral 17 is a delivery arm for delivering the wafer W between the processing station A2 and the aligner A4.
In the aligner A4, however, exposure of a circuit forming area is shifted and thereby the shape of a pattern deteriorates if the aligner vibrates during processing. Accordingly, a foundation is provided at the lower end side of the aligner, and the aligner is placed on this foundation, thereby preventing the vibration of the aligner.
Meanwhile, in the aforesaid coating and developing apparatus, when it is thought to increase the numbers of the coating units 11 and the developing units in order to improve a throughput, it is common to add units in a direction orthogonal to the direction of the arrangement of the cassette C in the cassette station A1. Also, there is the thought that only the coating units 11 are disposed in the processing station A2 and that a processing station including developing units is added at the next tier.
In such methods, however, if systems are added in any case, the distance between the transfer path 10 for the automatic transfer robot and the aligner A4 is lengthened. Hence, when the systems are added, the transfer path for the automatic transfer robot needs to be formed again in a different area, which causes a disadvantage that construction work increases in addition to work for the addition of the units and the processing station, resulting in a lot of trouble.